What was possibly wrong in my gel electrophoresis when I didn't see bands of DNA ladder, and genomic DNA sample on gel ? I could see bands of genomic PCR and RNA solution.
Thank you all of guys for sharing your opinions. From some opinions, I found out the possible error that my genomic DNA didn't show up because it was not pure (I forgot the detail that our group used a sample of DNA which was extracted from a previous lab and we didn't obtain an expected ratio for the purity of DNA. Then, we also used the impure DNA sample to do PCR, and finally used the amplified DNA for gel electrophoresis lab). However, the reason for DNA ladder didn't show up I'm not sure. I just can suppose that my groupmate who handled with DNA ladder solution possibly contaminated it.